The present invention relates to a heat-sensitive magnetic transfer element and more particularly to a heat-sensitive magnetic transfer element which allows a thermal printer to prepare a printed magnetic image recognized by a magnetic ink character reader.
The magnetic ink character reader (hereinafter referred to as MICR) can read and recognize the certain printed magnetic image, such as character, or mark, which is printed to bill, check, credit card, pass, traffic census card, or the like. A magnetic head in the MICR converts the variations of magnetic portions corresponding to various characters and marks into predetermined signals, and voltages are detected to recognize the characters and marks.
In that case, it is necessary that each of the characters and marks to be read by the magnetic head has a certain shape, dimensions and allowable ranges of dimensions in addition to the certain magnetic signal levels. Therefore, the allowable ranges as to E13B type face employed in American Bank Association are defined in JIS C 6251 (Japanese Industrial Standard).
E13B type face defined in JIS C 6251 consists of 10 numbers (0 to 9) and 4 special marks. According to JIS C 6251, a character height, a character width, a corner radius, allowable ranges of those and an allowable range of a void with respect to each character are described. In addition to E13B type face, CMC7 type face is well known as type face for MICR. CMC7 type face is formed by arranging 7 longitudinal bars with 2 kinds of intervals, and each of CMC7 type faces can be magnetically recognized by combinations of 2 kinds of intervals. Thus, CMC7 type faces consist of 10 numbers, 26 large alphabets and 5 special marks, and dimensions and magnetic property of CMC7 type face are determined by European Computer Manufactures Association.
The printed image of the above type face for MICR is formed by transferring a magnetic ink onto a receiving paper by an impact printer such as typewriter. The magnetic ink including a magnetic substance powder is coated and dried on a foundation such as plastic film to form a pressure-sensitive magnetic transfer element. Such a pressure-sensitive magnetic transfer element is disclosed in, for example, Japanese Patent Publication No. 21449/1970.
However, the use of the pressure-sensitive magnetic transfer element results in generating noise due to impact system, and further cannot perform high printing speed. In addition, the above transfer element tends to generate voids in the printed magnetic image.